Wollombi Valley Against Gas Extraction

Date: 06-Feb-10
Author: Graeme Gibson
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Attached is a presentation by Geodynamics in relation to its proposed Hot Rocks exploration in the Bulga area.

As did Sydney Gas in the past, and as did AGL up until recently, Geodynamics has put a buffer between the community and the company.  They have employed an intermediary.  Sydney Gas and AGL finally stopped doing this when they saw that the community was losing all confidence inn the companies because they couldn't speak to the company.  No doubt Geodynamics will also get rid of the buffer and speak to us directly when they lose the community by virtue of it.

In addition to the presentation, Geodynamics said:

• That in early 2,000 Pacific Power drilled 13 wells near Denman.  No hot granites.
• That Geodynamics took over the licences.
• That over the past few years, around Bulga, they have explored with seismic lines indicating a hot granite body at a depth of 4 kilometres. The main hot spot is under the World Heritage Listed Wollemi National Park, but they aren't allowed to drill there.  They have drilled 3 shallow wells to about 300 metres to see if they could infer the heat below.  Temperature gradient increased by about 57 degrees C in the most northerly well indicated sufficient temperature at 4 kilometres.
• Next step is to drill a 2 km deep hole through the coal seams and into the basalt which will give a temperature gradient upon which they can be more confident of the temperature of the granites below.
• The 4 klm deep hole, if they go to that stage, costs $20 to $30 million to drill.
• The 2 km hole will give gthem a "go" or "no".
• If they go o the granite at 4 km deep, they will look at the fractures, and maybe have to stimulate further fractures.  Dr. Gavin Mudd says that one of their stimulated fractures in Cooper Basin, where to date they have failed in their efforts to make the technology work after some years of failures, caused a tremor 6 on the Richter Scale. This apparently surprised them, as they were prepared for only a scale 3 event.
• The place where they are drilling is, and I think I recorded this correctly, is on two properties towards the end of the unsealed section of Wambo Road owned by Fredericks and Bracy and they will need access through Fenwick's property.
• They are apparently awaiting a change in legislation before they can drill the well.
• They are aware of the Bulga fault line, however claim it is stable.  They say they believe the risk to the fault line is very low, but it would be independently assessed with seismic survey to assess the risks.
• In relation to safety, I have mentioned the level 6 Richter Scale event, but they also had corrosion in the casing of the well which split at the surface in March, 2009 and had to be brought under control and plugged by international experts.  They learned they were using the "wrong steel".  They say they are learning and that conditions in the Hunter will be different !!!
• They need 1.5 megalitres of water which they will either truck in or seek a bore.
• If they are successful they would plan to build 4 x 50 megawatt power stations at Bulga (they have to be at the site of the hot rocks), each power station being the size of about 2 football fields.
• When asked why their experiment at Cooper Basin is taking so long, they said it was new technology, "groundbreaking" (intended pun or not?), the cost of drilling was much more expensive than they thought, had had "issues understanding what the reservoirs are", they are taking a measured approach.
• Drilling the well would take 120 days.  The life expectancy of the power station would be about 30 years.
• Still learning from Cooper Basin, and by the time they are in a position to build a power station at Bulga they should have built one at Cooper Basin where any problems will have been addressed.
• If the temperature of the rocks diminishes, or the temperature is not as hot as they hoped, they would use "another liquid" other than water.  Didn't say what, or what chemicals it would contain.
• Dr. Mudd was not happy with Geodynamics claim of no radioactivity level problem, he wanted the numbers and the research they had done to enable them to make that claim.
• A number of questions have been forwarded to Geodynamics and we await their answer.

• Presentation - Geothermal energy in the Hunter Valley
  A presentation by Geodynamics in relation to its proposed Hot Rocks exploration in the Bulga area. (2.28MB ppt file)

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